ONF 온앤오프 is a seven-member male idol group formed by WM Entertainment in 2017. The group consists of Hyojin, E-tion, J-Us, Wyatt, MK, U, and Laun. The group debuted on August 2, 2017, with their mini-album title track "ON/OFF."

The group name is short for "On N Off."

Pre-debut

Prior to joining WM Entertainment, U was a trainee at JYP Entertainment. MK trained at Starship Entertainment. In 2015, MK participated in Mnet and Starship Entertainment's survival program "No.Mercy" but was eliminated. During the group's first showcase, Laun revealed that he was a trainee at Big Hit Entertainment and used to train together with BTS.

All members made up WM Boys. WM Boys performed as B1A4's back-up dancers at the 2016 Dream Concert in Seoul.

Members J-Us, Laun, and Wyatt made a cameo appearance in labelmate B1A4's mini-drama VCR "The Class," and E-tion and Wyatt appeared in another B1A4 VCR called "Feeling." Hyojin, E-tion, J-Us, and Wyatt were featured as dancers in the Korean version of the web drama "Loss:Time:Life."

On May 25 2017, all members of WM Boys attended IDOLCON 아이돌콘 and performed "Original," a B-side track from their soon-to-be released debut album.

2017: Debut

The group released their debut track "ON/OFF" on August 2, 2017. The following day, the group held their debut stage at "M Countdown." On November 5, the group joined the survival show "MIXNINE" and all of the members passed the auditions. On October 28, Kim Hyojin ("ON" unit leader) was revealed as the male center for the show's first performance mission, "Just Dance."